**2.11 The effect of pH on the activity of glucose isomerase in red wine medium**

Homemade wines at different pH values; 4, 5, 6, 7, and 8, containing 1% w/v fructose as a substrate were tested at temperatures of 60 and 30°C for this experiment. The pH adjustments of samples were done with a 5 M NaOH solution. The samples were incubated at 150 rpm, 60 and 30°C, for 70 hours.
